Generally, a semiconductor manufacturing process comprises unit processes such as a thin film process for forming a dielectric layer and a conductive layer on a semiconductor substrate, a photolithographic process for patterning the dielectric layer and conductive layer to a desired pattern, a contact window process for connecting conductive material layers (or patterns) to each other, a chemical mechanical polishing (CMP) process for planarizing surfaces of the material layers, etc.
During the manufacturing processes, undesirable foreign bodies, e.g., small particles, metal impurities and organic contaminants, etc, may remain on the surfaces of material layers, thereby causing problems in subsequent processes or in a manufactured device. For instance, the foreign bodies remaining on an interface between conductive material layers may deteriorate contact resistance characteristics of the manufactured device. In addition, if an upper material layer is formed on a lower material layer with foreign bodies on a surface thereof, the upper material layer may exhibit bad step coverage, an irregular surface, or poor growth. Therefore, a cleaning process is performed to remove foreign bodies on a material layer between the unit processes.
SCI is a conventional cleaning solution used in semiconductor manufacturing and includes a mixture of hydrogen peroxide (H2O2), ammonium hydroxide (NH4OH) and deionized water. Although SCI does not cause particular problems to polysilicon, silicon nitride, and oxide, SCI contains hydrogen peroxide that causes problems to metals used in fabricating semiconductor devices because hydrogen peroxide is a strong oxidizer. For instance, the hydrogen peroxide corrodes various metals used in processes for fabricating semiconductor devices and has a disadvantage of requiring a high temperature for cleaning.
Therefore, a need exists for cleaning solutions that are capable of removing foreign bodies without corroding metals used in semiconductor fabrication, and cleaning methods using the cleaning solutions.